The invention relates to an electrical machine with a single-pole winding with a structure substantially comprising two bodies, whereby at least one of said bodies has a layered structure in the form of a laminated sheet-iron plate and at least one of said bodies is assembled in a segmented manner as a receiving body substantially comprising at least two carrier segments; whereby each of said carrier segments, which are structured layered on their own as well, is suitable for receiving in an operationally fixed manner at least two winding carriers in suitable cavities; and whereby said winding carriers each can be wound separately.
Such an electrical machine is known from DE-A 1 181 312. The layered and at the same time segmented structure of a machine body is expected to assure adequate venting of the electrical machine by making individual segments of such a laminated sheet plate shorter, so that additional venting channels are opened in this way.
An electrical machine that is structured in a similar way is known from German patent specification DE 196 43 561.
It is known since a long time in connection with electrical machines to make provision for single-pole windings for the purpose of avoiding overlapping of conductors in order to achieve a particularly compact winding. The problem in conjunction with such single-pole windings is that due to the constant width of the pole cores, which is desirable for making the flow density more uniform, an overall unsatisfactory groove filling factor is obtained as a consequence of the radially outwardly expanding grooves for receiving the windings.
Another problem of electrical machines is that in the event of a conductor fracture, either the rotor has to be replaced as a whole, or said component has to be completely newly rewound.
Therefore, for avoiding such drawbacks, an electrical machine is proposed in DE-PS 196 43 561 whose rotor has a structure substantially comprising two different types of segments. The one segment is a completely pre-wound, finished T-segment, which advantageously may be wound with the help of a machine, and the other segment is an X-segment. According to the instruction of said patent specification, the rotor or stator of an electrical machine can be manufactured in a simple way by plugging the respective segments together to obtain a rotor or a stator. In this connection, the pole segments are connected to each other by means of thin holding pins to obtain a rotor or a stator.
The advantage of this known solution lies in that it is possible to use pole segments that are already completely pre-wound and finished, and in particular wound with a machine. Such pole segments can be employed in conjunction with interior rotors, external rotors, or even in connection with axial-flow machines and linear motors.
However, in the course of practical realization of such an electrical machine it was found that it is difficult to assemble an armature or rotor from said pole segments. Because of the manufacturing tolerances achievable in connection with such components it was not possible to assemble a circular machine element. It was accordingly not possible to assemble the armature or rotor of an electrical machine from the pole segments described above.
Furthermore, it is not possible to simply reduce the number of the individual segment in order to facilitate the assembly because said number has a direct relation to the pole division or pole number desired in a given case for the respective electrical machine. Moreover, the aforementioned segmentation of a soft-magnetic body of the electrical machine leads to substantial variations in the width of the air gap, which is not acceptable especially in conjunction with electrical machines operating at high speeds. Furthermore, an air gap width varying beyond the periphery of the rotor leads to scatter loss impairing the efficiency, as well as to possible variations in the synchronism and output or the electrical machine.
Therefore, the invention is based on the problem to open up the widest possible field of application for the advantageous structure of an electrical machine comprising at least one body with a segmented structure.
Said problem is solved with an electrical machine as defined in the introductory part of the independent claim in that the carrier segments of the electrical machine are manufactured in such a way that the winding carriers are equally well usable for linear motors and rotational machines. This permits a manufacture according to the modular principle. Furthermore, the winding carriers are secured in a detachable manner, so that individual winding carriers can be replaced in the event of a conductor fracture or other defects. Furthermore, the electrical machine can be fitted with winding carriers depending on the power density desired in the given case. The modular construction thus permits an exact adaptation to the installation space or the requirements in the given case, first of all, whereby the fitting of the machine, furthermore, can be exactly adapted to said parameters. The present machine accordingly can be varied in almost any desired way with nearly no change in its manufacture.
According to said solution as defined by the invention, a distinction is made between carrier segments for building up a receiving body and winding carriers by segments. A carrier segment as defined by the invention is in each case suitable for receiving a plurality of winding carriers, at least two winding carriers.
The carrier segments, in each case decoupled from the given pole pitch, can be dimensioned in this manner in such a way that they cover in each case more than one pole pitch of the electrical machine. In conjunction with rotating electrical machines it is thus possible to assemble the rotor or stator from two, four, six, eight or another selectable number of carrier segments. Said number, however, should be as low as possible for manufacturing reasons.
The selection of the number of carrier segments to be assembled in a given case is, in this connection, entirely independent of the pole number of the respective electrical machine because only up to a defined number of winding carriersxe2x80x94said number being determined by the size of the carrier segmentxe2x80x94can be inserted in the carrier elements.
As opposed to the prior art, the deviations from the ideal measure in the dimensions of the individual components required for the assembly of the machine body, such deviations being unavoidable within the framework of the usual manufacturing tolerances, cannot add up in such a way that, as the final result, the machine body cannot be assembled. The number of carried segments used is for that purpose selected independently of the pole number of the machine and depending on the manufacturing accuracy and tolerances in a way such that the respective body of the electrical machine can be safely assembled.
Advantageous developments of the instruction as defined by the invention are specified according to the following dependent claims.
Owing to the fact that according to claim 2, each carrier segment by itself completely forms the respective cavities, an easier assembly of the machine is assured than if corresponding cavities were formed also between the segments.
The modular structure of the machine becomes even more efficient if the machine can be assembled from pre-fabricated laminated sheet-iron plates.
According to an advantageous development of the invention, the winding carriers are already completely wound before they are inserted in the respective receiving body. The winding carriers can be wound separately and with the help of machines in particular by employing the flyer technique.
The winding as such, but also the operationally fixed support of the windings is facilitated in that the winding carriers each have pronounced coil heads. Producing the winding carriers in the form of single-pole windings permits the formation of flat coil heads and thus extremely compact designs of machine construction.
The winding carriers can be connected with the respective receiving bodies in a simple manner by means of plug pins in a detachable and operationally fixed manner.
It may be necessary in conjunction with multiphase machines to arrange a plurality of separate windings on one single winding carrier. This, too, is substantially facilitated by the fact that the winding carriers can be pre-wound separately.
An embodiment of the winding carrier that is particularly advantageous with respect to both its manufacture and operation is specified according to claim 7.
Because of the special form of the winding carrier and the receiving body it is possible also with such a structure of the machine to form an at least nearly closed surface vis-a-vis the air gap. This assures uniform flow-through and thus the synchronism of the machine.
It is alternatively or additionally possible to secure each winding carrier by means of a projection that engages a corresponding guide groove of the receiving body.
A plurality of distinguishable windings can be advantageously arranged on the winding carrier.
According to a further development of the invention, the pole shanks are wound with a flat wire. As opposed to round wires such a flat-wire winding avoids the possible formation of cavities in the space of the grooves. The smooth-edged space of the groove, which preferably has a rectangular cross section, can be optimally filled in this way. A high groove filling factor increases the degree of efficiency of the respective electrical machine.
Owing to the fact that the receiving bodies each are structured as laminated sheet-iron plates in a way such that the individual layers are arranged offset, leaving free the cavity provided for receiving the completely wound, i.e. the finished pole shank of the winding carrier, the carrier segments are structured as a whole as laminated sheet-iron plates each having the highest density.
Avoiding additional air gaps between the adjacent carrier segments, the cogging achieved in this way substantially increases the possible flow through the respective electrical body because of the increased relative permeability constant xcexcr. Furthermore, the mechanical strength of the receiving body so cogged is increased.
According to a further improvement of said advantageous further development, the thickness of the laminated sheet plates employed for building up the receiving bodies can be freely selected depending on the machine output desired in the given case. The winding carriers to be pushed in remain unaffected thereof up to a certain limit.
A further increase of the efficiency of the electrical machine so structured is obtained in that the individual receiving bodies can be build up from grain-oriented transformer sheets, whereby the orientation is not lost even beyond the periphery of the electrical machine because of the segmented arrangement.
According to a further development of the invention it is possible within the framework of the latter to build up a compensated electrical machine by structuring the receiving body in a way such that receiving bodies can be pushed in on both sides, i.e. disposed both radially on the inside and radially on the outside, or disposed inside and outside in conjunction with linear motors.
Owing to the modular structure of the machine and the fact that it can be adapted at the same time in almost any desired way to the power density required in the given case it is possible to employ the machine anywhere where perfect adaptation to the available installation space is required. If it is designed in the form of a linear motor, for example, it can be mounted as a direct drive on a closed handling axle instead of attaching an additional linear motor next to the handling axle. A completely closed design offers many advantages especially in an aggressive environment.
According to claim 17, the electrical machine as defined by the invention can be advantageously employed both as a linear motor and a motor with an interior or external rotor. It is likewise possible also to build up synchronous, asynchronous, permanently excited or electronically commuted electric machines or direct drives. Furthermore, if the winding carrier is wired accordingly, the electrical machine as defined by the invention can be build up also in a simple way as a compensated motor.